Republicans Supporting Gay Marriage Write Supreme Court Amicus Brief

The issue of same sex marriage is dividing the Republican Party as a group of more than 80 prominent members of the GOP ranging from Dick Cheney's daughter to four former governors have signed an amicus brief before the Supreme Court advocating for the legalization of gay marriage.

One of the signers confirmed for ABC News the existence of the brief signed by the Republicans and said it would be submitted to the United States Supreme Court this week. The deadline to submit briefs is Thursday.

The document, known as an amicus or "friend of the court" brief, is being submitted in support of a lawsuit aiming to strike down Proposition 8, the California ballot initiative that passed in 2008 banning same sex marriage. The existence of the brief was first reported by the New York Times.

Republican elected leadership, like House Speaker John Boehner, as well as the platform, are staunchly against same sex marriage.

The American Foundation for Equal Rights (AFER), the group who brought the California lawsuit challenging Prop 8, released a list of the signers today including Cheney's daughter Mary Cheney.

Signers included former congresswoman Mary Bono Mack of California, former presidential candidate Jon Huntsman and Meg Whitman, who supported Prop 8 when she ran for governor of California in 2010. Representatives Ileana Ros-Lehtinen of Florida, Richard Hanna of New York and former GOP national chairman Ken Mehlman also signed. In addition, three former Massachusetts governors -- William Weld, Jane Swift, and Paul Cellucci -- along with former New Jersey governor Christine Todd Whitman are signers. The list also includes Republican attorney and Romney senior adviser Ben Ginsberg and other high profile GOP leaders, strategists, consultants, and staffers.

Some big name supporters of same sex marriage who have not signed the brief include former vice president Dick Cheney, former first lady Laura Bush, and former Secretary of State Colin Powell.

The fight against Prop 8 already had a big name conservative supporter in Theodore Olson, former solicitor general under President George W. Bush, who is one of the suit's two lead attorneys along with David Boies.

The court will hear arguments next month in the case and another important gay rights case that challenges the 1996 federal Defense of Marriage Act.

One of the signers is Nicolle Wallace, Republican strategist and former George W. Bush aide and John McCain campaign adviser. Wallace said the beginning of the group took place in 2010 when Republicans supportive of same sex marriage came together to fundraise for the legal effort. But even in 2004 during Bush's re-election campaign working alongside Mary Cheney everyone on the campaign was aware there were disagreeing opinions on the ticket.

"For a long time those of us who sort of have always been on the pro-gay marriage side were quietly aware of others who had this view, but what's tremendous now is I can't think of any issue that has moved with greater speed than this one," said Wallace, who is an ABC News contributor.

She said the "power of the legal argument had a lot more to do with persuading the majority of Republicans on the brief than any political pressure."